<template>
<div class="todo-footer" v-show="total">
<label>
  <input type="checkbox" v-model="isAll">
</label>
  <span>
  <span>已完成{{doneTotal}}</span>/全部{{total}}
  </span>
  <button class="btn btn-danger" @click="clearAll"> 清除已完成任务</button>
</div>
</template>

<script>
export default {
name: "MyFooter",
  props:['todos'],
  computed:{
  //计算属性的完整版
  isAll:{
    get(){
      return this.doneTotal === this.total && this.total>0
    },
    set(value){
      this.$emit('cheakAllTodo',value)
    }
  },
  //总数
    total(){
      return this.todos.length
    },
    doneTotal(){
      //统计数组中勾选的个数
      return this.todos.reduce((pre,current)=>{
      return pre + (current.done ? 1 : 0)
      },0)
    }
  },
  methods:{
    clearAll(){
   this.$emit('clearAllTodo')
    }
  }
}
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}

</style>